i have a gt 130 tdi and i let it tick over while i sort myself out like turning heater on stereo nice and loud and of course i put my seat belt on then just pull away. i surpose it takes about a minute to get nice and comfy so very little warm up if any really.
i would walk away as well as if you want to let it warm up first to the right temp you will be there a while as mine takes about 10mins to warm up to 90 on the temp gauge in this cold weather.